Ontario Geological Survey
Permanent Link to this Record:
MDI42D11NE00005
| Record Name(s) | Horace Cove - 1897, Cosen's Showing - 1897, St. Mary's Bay - 1897, South Slate Island - 1897, F Vein - 1962 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Prospect |
| Date Created | 1991-Apr-01 |
| Date Last Modified | 2022-May-06 |
| Created By | |
| Revised By |
Primary Commodities: Gold
Township or Area: Slate Islands Area
Latitude: 48° 38' 17.73" Longitude: -87° 2' 12.34"
UTM Zone: 16 Easting: 497291.85 Northing: 5387244.65 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 42D11NE
Point Location Description: Two adits.
Location Method: Conversion from MDI
Access Description: The Horace Cove Occurrence is located on the northwest corner of St. Mary's Bay (Horace Cove). A second gold occurrence, the Cosen's Occurrence or South Slate Island Occurrence, is located 240 m northeast of the Horace Cove Occurrence. Access is via boat across Lake Superior. A boat launch south of the town of Terrace Bay allows water access to the Slate Islands.
Circa 1897: Prospecting was conducted. Two adits, approximately 120 m apart, were driven 7.5 m and 51 m respectively, reportedly in the William Point area (known as the Patterson (S) occurrence). Mining was reported. 1960: Canadian Aero Service Ltd. conducted airborne EM and magnetometer geophysical surveys for Kimberly-Clark of Canada Limited. 1961-62: Trenching, mapping and sampling were conducted by Kimberly-Clark of Canada. 1963: Upper Canada Mines Limited, Junior Frood Mines Limited and Cadamet Mines Limited drilled 6581 feet. 1985: The Slate Islands were designated a Provincial Park and withdrawn from staking.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 63.3236 | 42D10NW0001 | 42D10NW0001 |
Province: Superior
Subprovince: Wawa
Terrane: Wawa-Abitibi
Belt: Schreiber-Hemlo
Geological Age: Archean
Dec 07, 2005 (B Schnieders) - Sage (1991) decribes the gold mineralization: 'Gold mineralization occurs in three ways . These are (1) in association with pyrite within the quartz-carbonate veins; (2) as flakes and thin sheets along the flanks of the quartz-carbonate veins; and (3) as thin sheets or flakes along schistosity planes of the rocks enclosing the quartz-carbonate veins.' Schnieders et al. 1996, decribed the occurence as; ' an oblique vein set of quartz-carbonate veins within a highly deformed and altered host rock. The quartz veins are generally narrow (5 to 15 cm) and contained visible gold, pyrite, siderite, or iron carbonate and minor tourmaline. The quartz veins vary from massive to crack-seal in nature, and display a wide range of strikes from north-west to north-east; they likely represent a conjugate vein set within a deformation zone. The main deformation zone and schistosity strike 90 degrees and dip 80 degrees S. The host rock displays a porphyritic texture and was variably altered to a carbonate-sericite schist. Green mica shards or clasts were observed within the host rocks. The altered host rocks and veins extend for over several hundred metres in both width and strike length. Highly deformed and carbonatized host rocks of a similar nature to the Slate Islands have been observed in the Heron bay area.
Dec 07, 2005 (B Nelson) - The occurrence is classed as a 'lode gold' deposit. The Slate Islands are underlain by Neoarchean metavolcanic and metasedimentary rocks, which have been intruded by diorite, syenite, gabbro and diabase. Gold bearing quartz veins occur wihtin sericite-carbonate alteration zones in schist, porphyry and diorite. Sage (1991) describes the gold mineralization as occuring in three ways: 1). In association with pyrite within the quartz-carbonate veins. 2). As flakes and thin sheets along the flanks of the quartz-carbonate veins. 3). As thin sheets or flakes along schistosity planes of the rocks enclosing the quartz-carbonate veins. Sage (1991) described a quartz vein set with veins averaging 10.7 cm in width and 5.5 m in length. The veins are within a major deformation zone believed to occupy an inflection point within a major fold structure, presumably in a position of dilatancy. Schnieders et al. (1996) observed an oblique vein set of quartz-carbonate veins within a highly deformed and altered host rock. The quartz veins were generally narrow (5 to 15 cm). The quartz veins vary from massive to crack-seal in nature, and display a wide range of strikes from northwest to northeast; they likely represent a conjugate vein set within a deformation zone. The main deformation zone and schistosity strike 90 degrees and dip 80 degrees south. The host rock displays a porphyritic texture and was variably altered to a carbonate-sericite schist. Green mica shards or clasts were observed within the host rocks. The altered host rocks and veins extend for over several hundred metres in both width and strike length. Highly deformed and carbonatized host rocks of a similar nature to the Slate Islands have been observed in the Heron Bay area. The St. Mary's Bay zone is 1000 feet long and 200 feet wide. The Cosen's zone is exposed intermittently with widths up to 50 feet.
| Rock Type | Rank | Composition | Texture | Relationship | Diorite | 1 | Diorite | Host |
|---|---|---|---|---|
| Syenite | 2 | Near | ||
| Gabbro | 3 | Gabbro | Near | |
| Diabase | 4 | Diabase | Near | |
| Schist-Unsubdivided | 5 | Host | ||
| Porphyry-unsubdivided | 6 | Host |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Gold | Economic | Ore | ||||
| 2 | Pyrite | Economic | Ore | ||||
| 1 | Quartz | Economic | Gangue | ||||
| Quartz | Alteration | Silicification | 1 | Unknown | Veins | ||
| Carbonate | Alteration | Carbonatization | 2 | Unknown | Disseminated | ||
| Tourmaline | Alteration | Tourmalinization | 3 | Unknown | Disseminated | ||
| Sericite | Alteration | Sericitization | 4 | Unknown | Disseminated |
Dec 07, 2005 (B Nelson) - Grab samples collected by staff of the Schreiber-Hemlo Resident Geologist's Office assayed nil to trace Au, except sample 91-BSI-03, which assayed 0.011 oz/ton Au and 91-BSI-05 which assayed 3.149 oz/ton Au and 0.27 oz/ton Ag. Sample 91-BSI-05 contained visible gold in hand specimen. Sample 95-BHC-02, which was a grab sample of a 5 cm wide quartz vein at the nose of a fold, assayed 3.95 oz/ton Au and nil Ag. Historically, individual grab samples have assayed up to 4.92 oz/ton Au across a width of 2 inches. The best assay over a greater width was 0.20 oz/ton Au across 3 feet from the #14 vein.
| Commodity | Analytical Method | Digestion Method | Result | Unit | Limit | Qualifier |
|---|---|---|---|---|---|---|
| Gold | Unknown | 3.95 | oz/t |
Date: Feb 04, 1997
Geologist: B Nelson
Notes: Resident Geologist personnel visited the occurrence September 21, 1989 and July 8, 1991.
Map - Precambrian geology, Slate Islands
Publication Number: M2523 Scale: 1:10,000 Date: 1991
Author: Sage R.P.
Publisher Name: Ontario Geological Survey
Location:
Mono - Geology of the Slate Islands
Publication Number: OFR5435 Page: 207, 214 Date: 1984
Author: Sage R.P.
Publisher Name: Ontario Geological Survey
Location:
Part - Slate Islands, Lake Superior
Publication Number: ARV27-01.004 Page: 155-167 Date: 1998
Author: Parsons A.L.
Publisher Name: Ontario Bureau of Mines
Location:
Thesis - Gold Occurrences on the Slate Islands of Lake Superior
Publication Number: BSc Thesis Date: 1963
Author: Nichols, L.C.
Publisher Name: Queen's University
Location: Thunder Bay RGP
File - Schreiber-Hemlo Resident Geologist Mineral Deposit Files, Thunder Bay office
Publication Number: Min Dep Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
Map - Geological series, Slate Islands, District of Thunder Bay
Publication Number: P0997 Scale: 1:15,840 Date: 1975
Author: Sage R.P., Treacher K.W., Meloche D., Bathe D.
Publisher Name: Ontario Division of Mines
Location:
Mono - Mineral Occurrences in the Nipigon-Marathon Area, Volumes 1 and 2.
Publication Number: OFR5951 Page: 82-84 Date: 1996
Author: Schnieders B.R., Smyk M.C., Speed A.A., McKay D.B.
Publisher Name: Ontario Geological Survey
Location:
MonoMap - Precambrian geology, Slate islands
Publication Number: R264 Date: 1991
Author: Sage R.P.
Publisher Name: Ontario Geological Survey
Location:
Mono - Gold deposits of Ontario, part 1, districts of Algoma, Cochrane, Kenora, Rainy River, and Thunder Bay
Publication Number: MDC013 Page: 289-290 Date: 1971
Author: Ferguson S.A., Groen H.A., Haynes R.
Publisher Name: Ontario Dept. of Mines and Northern Affairs
Location:
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